CT Coronary Angiography
A focused scan for Coronary arteries, Calcium score, Blockages.
Overview
Examines Coronary arteries, Calcium score, Blockages. Performed at an NABL-accredited Meridian Health centre with a same-day report and a free doctor review.
The full panel
3 areas across 1 groupEvery parameter, grouped by body system — no clicking to expand.
What this scan measures
The coronary arteries themselves, imaged non-invasively with ECG-gated CT after an iodinated contrast injection. It shows plaque in the artery wall, the degree of narrowing, and — from a preliminary non-contrast series — a coronary calcium score.
It is used mainly in people with chest pain at low-to-intermediate probability of coronary disease, where its real strength is its ability to rule disease OUT: a scan showing normal coronary arteries makes significant coronary narrowing very unlikely and can avoid an invasive angiogram. It is also used to assess anomalous arteries and to check bypass grafts.
Symptoms that lead to this scan
- Chest pain or tightness on exertion
- Breathlessness with cardiac risk factors
- An equivocal or inconclusive treadmill test
- A strong family history of early coronary disease
- Assessment of atypical chest pain before invasive testing
Understanding your results
A calcium score of zero indicates no detectable calcified plaque and is associated with a low short-term event risk, though it does not exclude soft, non-calcified plaque. Scores are commonly banded as minimal (1–99), moderate (100–399) and extensive (400 and above) on the Agatston scale. Stenosis is reported as a percentage narrowing, but a CT tells you about anatomy, not about whether a narrowing is actually limiting blood flow — that question is answered by a stress test or an invasive pressure measurement. Heavy calcification can itself obscure the lumen and limit accuracy.
Indicative only. Reference ranges vary between laboratories and between testing methods, and shift with age, sex and pregnancy — always read your own result against the range printed on your own report, with the doctor who ordered it.
| Parameter | Indicative range | Unit |
|---|---|---|
| Coronary calcium score — none detected | 0 | Agatston |
| Coronary calcium score — minimal to mild | 1–99 | Agatston |
| Coronary calcium score — moderate | 100–399 | Agatston |
| Coronary calcium score — extensive | 400 and above | Agatston |
Why the preparation matters
Fast for four hours, and avoid caffeine — coffee, tea, cola, chocolate and energy drinks — for at least 12 hours, because the images are only sharp when the heart rate is low and regular, usually below about 65 beats per minute. For the same reason you may be given a beta-blocker before the scan and asked to lie quietly beforehand; if you already take one, take it as usual. Sublingual nitroglycerin is often given to dilate the arteries. Kidney function is checked before contrast. Tell the team about sildenafil-type medication, which must not be combined with nitrates.
CT Scan — safety and who should not be scanned
Full CT Scan guideCT uses considerably more ionising radiation than a plain X-ray — the trade for the detail it produces. Published reference figures put a head CT at roughly the background radiation of several months and a chest or abdominal CT at roughly a few years' worth. That is a risk worth taking when the scan will change management, and not worth taking when it will not, which is why CT is requested selectively rather than as a screening test. Modern scanners use iterative reconstruction and automatic dose modulation to keep the exposure as low as the diagnostic question allows.
- Pregnancy
- Always declare it. CT of the abdomen or pelvis delivers a direct dose to the fetus and is avoided unless the scan is genuinely necessary and no alternative — usually ultrasound or MRI — will answer the question. Head and limb CT can sometimes proceed with shielding after a specific discussion.
- Previous severe reaction to iodinated contrast
- A past reaction with rash, swelling, breathing difficulty or collapse must be reported before any contrast study. The scan may be done without contrast, with premedication, or replaced by a different test. Simple warmth, flushing or a metallic taste during a previous injection is a normal sensation, not an allergy.
- Impaired kidney function
- Iodinated contrast is cleared by the kidneys, so a recent creatinine or eGFR is checked before contrast studies. With significantly reduced function the scan may be done without contrast, or with hydration and dose adjustment as directed by the radiologist.
- Metformin, and uncontrolled thyroid overactivity
- Bring your medication list. Metformin is sometimes withheld around a contrast study in people with reduced kidney function, and iodinated contrast can destabilise untreated hyperthyroidism — both are managed with a plan rather than a refusal, provided the team knows.
- Inability to lie still, or claustrophobia
- The bore is short and open, so claustrophobia is far less of a problem than with MRI, but movement blurs the slices and may make a scan non-diagnostic. Tell the team if pain, tremor or anxiety will make stillness difficult; positioning aids and, rarely, sedation can be arranged.
- Table weight and bore limits
- Every scanner has a stated maximum table weight and aperture. Mention any concern when booking so the appropriate scanner is allocated, rather than discovering it on the day.
Who should consider this scan
- People with chest pain at low-to-intermediate risk of coronary disease
- Anyone with an inconclusive stress test
- Adults with a strong family history of premature heart disease
- Patients with atypical symptoms where invasive testing is being avoided
- People with previous bypass grafts under assessment
Conditions it helps detect
How it works
Patient stories
96% recommend“The phlebotomist arrived exactly on time and was gentle. My report came in five hours with a doctor’s note.”
“Booked at night, sample collected next morning. The parameter breakdown is genuinely thorough.”
“Loved the free doctor review — she walked me through my vitamin D and thyroid results clearly.”